How to index a matrix

Hello,

I would like to replace zeros with indexing, ie 1 to 26, and then replace last zero with a -2 please:

clc; clear; %Matrix size columns=10; rows=4; %Blank matrix X = zeros(4,10);

%Fill matrix (1st row & first column) newrow =-ones(1,columns); % the row to replace row 1 with newcolumn=-ones(rows,1); % the column to replace column 1 with

X(1,:)= newrow ; % replace row 1 in a with new

X(:,1) = newcolumn(:) % replace column 1 in a with new

==================================================================== >> X =

    -1    -1    -1    -1    -1    -1    -1    -1    -1    -1
    -1     0     0     0     0     0     0     0     0     0
    -1     0     0     0     0     0     0     0     0     0
    -1     0     0     0     0     0     0     0     0     0

Answer 1

[Star Strider]

I am not certain what result you want, so here are two options:

zi = find(X == 0);
X(zi) = [1:26 -2]';                     % Option #1
X(zi) = reshape([1:26 -2], [], 3)';     % Option #2

EDIT —

Option #1: 
X =
  -1    -1    -1    -1    -1    -1    -1    -1    -1    -1
  -1     1     4     7    10    13    16    19    22    25
  -1     2     5     8    11    14    17    20    23    26
  -1     3     6     9    12    15    18    21    24    -2

Option #2: 
X =
    -1    -1    -1    -1    -1    -1    -1    -1    -1    -1
    -1     1     2     3     4     5     6     7     8     9
    -1    10    11    12    13    14    15    16    17    18
    -1    19    20    21    22    23    24    25    26    -2